Stitch-forming mechanism for sewing machines



March 10.1925. 1,528,941

J. R. M OFFATT STITCH FORMING MECHANISM FOR SEWING MACHINES Filed March 2, 1918 3 Sheets-Sheet 1 RM mm Z alien-nu,

March 10,1925. 1,528,941

' J. R. MOFFATT' STITCH FORMING MECHANISM FOR SEWING MACHINES Filepl Marsh 2, 1918 3 Sheets-Sheet 2 alum" l a vweutoz J. R. MOFFATT STITCH FORMING MECHANISM FOR SEWING MACHINES Filed March 2, 1918 3 Sheets-Sheet 5 Patented Mar. 10, 1925.

UNITED STATES PATENT OFFICE.

JAMES R. MOFFATT, OF CHICAGO, ILLINOIS, ASSIGNO'R TO UNION SPECIAL MACHINE COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

STITCH- FORMING MECHANISM FOR SEWING MACHINES;

Application filedMarch '2, 1918. SerialNo. 220,046.

To all whom it may com-era Be it known that I, JAMES R. Mo rrA'rr, a citizen of the United States,.resid1ng at Chicago, in the county of (look, State. of

Illinois, have invented certain new and use ful Improvements in StitclrForming Mechanismfor Sewing Machines, of which the following is a description, reference being had to the accompanying drawing, and to the figures of reference marked thereon.

. The invention relates to new and useful in'iprovements in stitch forming mechanisms for sewing machines and more particularly to the devices for laying a cross thread be tween and connecting needle threads on the upper surface of the fabric.

An object of the invention is to provide a stitch forming mechanism having a stationary deflecting finger and an oscillating hook cooperating with said finger for forming loops 'in a cross thread, which. deflecting finger is supported by an arm capableof being adjusted about the axis of oscillation of the lever carrying the thread hook.

A further object of the invention is to-pro vide a device of the above character wherein the deflecting finger and the oscillating lever, carrying the hook, are mounted on a common member which maybe raisedor lowered relative to the presser foot for positioning the hook and the Y deflecting finger.

A still further object of the'invention is.

to provide a device of the above character wherein the deflecting finger is adjustably carried by a split sleeve surrounding the presser bar, which sleeve may be adjusted angularly about the bar or lengthwise of the bar and held in adjusted positions.

A still further object of the invention is v to provide a device of the above character wherein the lever carrying the hook is mounted to oscillate on the split sleeve ca pable of being adjusted longitudinally of the presser foot bar.

These and other objects will in part be obvious and will in part be hereinafter more fully disclosed. V

In the drawings, which show by way of illustration, one embodiment of the invention:

Figure 1 is a view partly in front elevation and partly in section, showing a portion of a sewing machine having my improvements applied thereto; a

Fig. 2 is a view of the machine from the rear thereof;

Fig. 3 is a view partly in section and part ly in. top plan, showing the work support, the deflecting finger, the thread hook, the lever for supporting the hook and the link for oscillating the lever;

Fig. 3 is a detail View showinga portion of the machine in end elevation;

Fig. 4 is a perspective View of the presser foot, a portion of the needles, the thread hook, the lever carrying the same, the link for oscillating the lever, the thread deflecting finger and the arm supporting said finger; I I I Fig. 5 is a diagrammatic view sl'lowing the joined fabric sections; I

Fig. 6 is a detail showing thesplit sleeve.

My invention is directed particularly to an improved or modified form of the mechanismfor laying a cross thread in loops between and connecting needle threads, shown and described in my prior Patent'No. 1,405; 855 granted February 7, 1922.

In the present embodiment of the invention, the thread hook is carried by an oscillating lever which is: mounted on a split sleeve, and this sleeve is carried by the.

presser bar and is capable of being adjusted longitudinally thereon. The lever is oscil-v lated by a link connection with an arm carried bya cross shaft at the rear of the machine and the cross shaft is operated by an eccentric strap co-operating with an eccentric on the main shaft beneath the work support. The threadfinger is carried by an arm which is mounted on the split sleeve and which is capable of angular adjustment on the sleeve so that the position of the thread arm may be shifted and as it is shifted the thread finger will bemoved concentrically about the axis of oscillation. of the lever carrying the thread hook.

Referring more in detail to the drawings,

lever which is of the usual construction. (lo-operating with the needles beneath the work support is a single threaded looper 10, which is mounted on a looper carrier 11. The looper carrier is pivoted at 12 to a support 13 and the looper carrier is oscillated on the support by a link 14. The looper support is oscillated, for giving sidewise or transverse movements to the looper, by an eccentric strap 15, (see Fig. 2 of the drawings). This eccentric strap co-operates with an eccentric on the main shaft 16.

Mounted in the overhanging arm 4 is a presser bar 17 which supports a presser foot 18. This presser foot may be of suitable construction for carrying out the purposes of the machine to which my invention is applied. I have shown a machine which is especially adapted for trimming the edges of two fabric sections and subsequently uniting said sections by stitching threads which join the fabric sections and cover the meeting edges thereof. The presser foot is provided with a guide slot 19 which extends from its extreme front end rearwardly substantially in the line of feed and terminates in front of the needle opening 20 in the presser foot. lrlounted in the presser foot a fixed trimming blade 21. Co-operating with this trimming blade is a movable blade 22 which is carried by a lever 23 oscillated bv a link 2% which is connected to the needle lever. Fabric sections to be united have their ed es upturned and as these upturned edges pass through the slot they will be trimmed. The presser foot is preferably constructed so as to overlap slightly the trimmed edges. This presser foot per se forms no part of my invention.

After the fabric sections have been trimmed and the edges overlapped or abutted the needles 6, 7 and 8 pass down through the sections. The left hand needle passes through the fabric section F only, as shown in Fig. 5, while the right hand needle passes through the fabric section F only. The central needle passes through both the fabric sections. The needle threads of the needles 6, '7 and 8 are indicated respectively at 6, 7 and 8', in Fig. 5 of the drawings. The looper thread is indicated at Z, while the cross thread is indicated at c.

The present invention, as above noted, is directed particularly to the devices for handling this cross thread. The trimming mechanism per se forms the subject matter of my prior Patent No. 1,d03,807, granted January 17,1921.

The cross thread laying mechanism consists of a thread hook 25. This thread hook is curved about the axis of the presser bar 17 as a center. The hook is formed with a notched end 26 for engaging the thread. Said hook is carried by a vertical shank 27 which is fixed at 28 to a lever 29. The lever 29 is fulcrumed on a split sleeve 30. This split sleeve 30 is secured to the presser bar 17. The lever is free to oscillate on the sleeve. A link 31 is connected to a ball stud 32 mounted at 33 in the lever 29. This link 31 at its other end is connected to a ball stud 3% carried by a depending arm 35 attached to a cross shaft 36 which is mounted to oscillate in bearings 37 and 38. An arm 39 is clamped to this cross shaft by suitable screws 40. This arm 39 carries a ball stud ll with which an eccentric strap 42 is connected. The eccentric strap co-operates with an eccentric on the main shaft 16. As the main shaft is rotated the shaft 36 will be oscillated and the arm 35 and link 31 will in turn oscillate the lever 29 carrying the thread hook. Co operating with this thread hook is a thread deflecting finger 43 extending in a sub stantially radial direction from the center of the presser bar 17. Said thread finger is carried by a shank at which is mounted in an arm as carried by a split collar -il6. The collar to is shaped to engage the lower end of the split sleeve 30. A clamping screw 47 secures this collar l6 to the split sleeve and in turn secures the sleeve to the presser bar 17'. The collar 46 serves to support the lever 29 at its low-er face and a flange on the split sleeve 30 holds the lever 29 from vertical movements 011 the split sleeve. By loosening the screw 1-7 the split sleeve may be raised or lowered on the presser bar 17 and this will simultaneously raise or lower the thread finger and the thread hook so that they may be properly positioned to clear the presser foot and to lay the thread for the needles. The cross thread, indicated at c in the drawings is led from. a suitable supply through a thread eye 48, thence through a tension 49 and thence through a thread eye 50. From the thread eye 50 the cross thread passes through a thread eye 51 carried by and movable with the needle bar. From the thread eye 51 the cross thread leads downwardly and is controlled and handled by the thread hook and the thread deflecting finger above described. A thread arm 52 carried by the needle lever engages the cross thread and pulls said cross thread from the supply. lVhen the three needles are clear down the thread hook is at the extreme rear end of its stroke, the thread eye 51 is at the lower end of its stroke and is so disposed relative to the finger 43 as to draw the thread forward on the finger to a pointadjacentthe forward end thereof. The thread eye 51 is positioned in front of the support therefor so as to be substantially over the forward end of the finger as, and, there fore, this thread eye will cause the thread on the finger to be drawn forward, as stated the cross thread to be deflected or slide,

back on the finger and this backward movement of the thread on the finger carries the cross thread so that it will lie between the needles 7 and Son the next downward movement of the needles. In other words, while the thread hook is forming the loop in the cross thread and the thread deflecting finger is positioning the cross thread, as stated above, the needles have risen to the extreme upper end of their stroke and on their return movement the needles 7 and 8 will straddle this cross thread, as stated above.

Of course, the thread deflecting finger may be shaped soas to position the cross thread between the needles 6 and 7 if desired. Said thread deflecting finger has a shoulder formed thereon, indicated at 52 which limits the rearward movement of the thread, due to the pull of the thread hook thereon and this shoulderpositions the cross thread accurately so that it will lie between the two needles desired.

The thread deflecting finger may be readily adjusted in the supporting arm and it may also be adjusted about the axis of the presser bar as a center by the shifting of the collar carrying the arm on the split sleeve. As above noted, the thread deflecting finger and the hook may be both raised and lowered if desired by raising and lowering the split sleeve.

It is obvious that minor changes in the details of construction and the arrangement of parts may be made without departing from the spirit of the invention as set forth in the appended claims.

Having thus described m invention, what I claim as new and desire to secure by Letters Patent, is

1. The combination with a plurality of needles and a complemental stitch forming device, of a thread hook for forming a loop in a cross thread for certain of said needles to enter, a deflecting finger for the cross thread, said, finger being shaped so as to cause said cross thread to slip rearwardly thereon as the. hook pulls on the cross thread and means for positively limiting the rearward movement of the thread on thefinger so that on strand of the loop in said cross thread may be properly positioned relative to the needles.

2. The combination with a presser foot,

a presser bar carrying said presser foot, a plurality of needles and a complemental stitch forming device, of a thread hook for forming a loop in a. cross thread for certain of said needles to enter, a thread deflecting finger against which the cross thread is drawn by the'hook, said thread deflecting finger being shaped so as to cause the cross thread to slide thereon rearwardl'y and thereby position one strand of the loop between the needles and means common to the thread hook and the thread deflecting finger and mounted on said presser bar for supporting the said thread hook and said finger- 3. The combination with a plurality of needles and a complemental stitch forming device, of a thread hook for forming a loop in a cross thread for certain of said needles to enter, a thread deflecting finger against which the cross thread is drawn by the hook,

said thread deflecting finger being shaped so as tocc-ause the cross thread to slide rear wardly thereon for positioning one strand of the loop between the needles, a lever for supporting and oscillating the thread hook, an arm for supporting the thread deflecting finger, and means for supporting said arm whereby it may be adjusted about the axis of oscillation of said lever.

4;. The combination with a plurality of needles-and a complemental stitch forming device, of a thread hook for forming a loop in a cross thread for certain of said needles to enter, a thread deflecting finger against which the cross thread is drawn by the hook,

said thread deflecting finger being shaped so as to cause the cross thread to slide rearwardly thereon for positioning one strand of the loop between the needles,a lever for supporting and oscillating the. thread hook, a link connected to said lever, across shaft, an arm mounted on the cross shaftand connected to said linkand means for oscillating said cross shaft.

5. A sewing machine including in combination, a work support, an overhanging arm, a presser foot, a presser bar carrying said presser foot, a plurality of needles and a complementary stitch forming device cooperating therewith, a thread hook for laying a cross thread so that the same may be stitched down by the needle threads, a lever supporting said hook, means for mounting said lever whereby the same oscillates about the presser bar as an axis, a link connected to said lever, a cross shaft carried by the overhanging arm, a depending arm carried by the cross shaft and connected to said link, a main shaft beneath the work support, an eccentric thereon, an eccentric strap co-operating with said eccentric and connected with said cross shaft for oscillating the same and a thread deflecting finger against which a cross thread is drawn by the hook, said finger being shaped so as to cause the cross thread to slide rearwardly thereon for positioning one strand of the loop in the cross thread between the needles.

6. A sewing machine including in combination a work support, an overhanging arm, a presser foot, a presser bar carrying said presser foot, a plurality of needles and a complemental stitch forming device cooperating therewith, a thread hook for laying a cross thread so that the same may be stitched down by the needle threads, a lover supporting said hook, means for mounting said lever whereby the same oscillates about the presser bar as an axis, a link connected to said lever, a cross shaft carried by the overhanging arm, a dependingarm carried by the cross shaft and connected to said link, a main shaft beneath the work support, an eccentric thereon and an eccentric strap co-operating with said eccentric and connected with said cross shaft for oscillating the same, a thread deflecting finger co-operating with said thread hook for po sitioning the cross thread relative to the needles and means for supporting said thread deflecting finger on said presser bar.

7. The combination of a work support, a presser bar, a presser foot carried thereby, a needle bar, a plurality of needles carried by said needle bar, a complemental stitch forming device co-operating with the needles beneath the work support, a thread hook co-operating with said needles above the work support for laying a cross thread in loops to be stitched down by the needle threads, a thread deflecting finger for engaging the cross thread and positioning the same relative to the needles, a thread guide carried by the needle bar for guiding the cross thread, said thread guide being positioned so as to move the cross thread forward on the finger and position the same for engagement by the thread hook, said thread deflecting finger being shaped so that the pull of the thread hook on the cross thread will cause the cross thread to move backwardly on the finger, said thread deflecting finger having a shoulder for limiting the rearward movement of the cross thread.

8. The combination of a work support, a presser bar, a presser toot carried thereby, a needle bar, a plurality of needles carried by said needle bar, a complemental stitch forming device co-operating with the needles beneath the work support, a thread hook co-operating with said needles above the work support for laying a cross thread in loops to be stitched down by the needle threads, a thread deflecting finger for en gaging the cross thread and positioning the same relative to the needles, a thread guide carried by the needle bar for guidii'ig the cross thread, said thread guide being positioned so as to move the cross thread forward on the finger and position the same for engagement by the thread hook, said thread deflecting finger being shaped so that the pull of the thread hook on the cross thread will cause the cross thread to move backwardly on the finger, said thread deflecting finger having a shoulder for limiting the rearward movement of the cross thread, a lever supportingand oscillating the thread hook, a collar having an arm for supporting the thread deflecting finger, a split sleeve mounted on the presser bar and supporting said lever and said collar and means for clan'iping the collar and the split sleeve to the presser bar.

In testimony whereof, I aflix my signature, in the presence of two witnesses.

JAMES R. MOFFATT.

lVitnesses S. GEORGE TATE, RALPH S- KELso. 

